1. Field of the Invention
This invention relates to a melting tank with a batch loading channel, with a channel covering that has an exhaust gas flue and a loading opening can be closed by a loading door or a loading flap during operation of the melting tank and can be opened for inserting the batch.
2. Description of Related Art
During batch loading in particular, such melting tanks often cause heavy dust contamination and gas formation at the loading opening, wherein portions of the batch or furnace atmosphere are released into open air. These harmful emissions must be captured. In addition, interaction with the batch components leads to an attack on the material of the loading channel and the loading door or flap that closes the loading opening. Furthermore, these materials are deposited on the parts and must be removed using expensive cleaning or repair measures.
For a melting tank of the mentioned type, it is one object of this invention to easily capture the emissions occurring when loading batches in the region of the loading door or flap and the loading channel and to reduce their harmful effects in the region of these apparatus parts.
This object is achieved according to this invention because during operation of the melting tank, a constant air stream is introduced into the loading channel with nozzles in the closed loading door or flap. During the loading of batches, the loading door or flap is moved sufficiently far so that the nozzles are moved out of the area of the loading channel, and the loading door or flap covers the region underneath the channel covering with a suction device. A region of the loading opening underneath the channel covering is opened for a loading device.
With this configuration, during the operation of the melting tank, an air pocket is created underneath the exhaust gas flue of the loading channel. This air pocket essentially prevents the penetration of contaminants from the surrounding air into the melt and prevents the advance of particles and exhaust gas out of the melting system into the loading channel and thus into the surroundings. Therefore, deposits are prevented in the loading channel and attacks by the aggressive substances on the material of the loading channel are minimized. In addition, the cooling leads to considerably less material stress. The overall service lifetime of the relevant apparatus parts is thus lengthened and cost-intensive cleaning and repair work is decreased.
While loading the batch, a significant part of the upper portion of the loading channel is closed by the moved loading door or flap, so that burst-like currents of exhaust gas, particles and exhaust gas, occurring during the loading of the batch can be effectively suctioned off by the suction flue or the suction device that is moved into the loading opening in the lower region of the loading channel when the loading door or flap is moved into the opened position. Thus, the emissions are clearly reduced. In addition, the formation of a gas stream is positively affected by the loading device.
The construction of the system remains simple and the system parts are exposed to reduced deposits of harmful material, so that as a whole, the service life of the parts is increased.
For introducing an air stream into the loading channel, according to one embodiment the loading door has an air connector that connects to nozzles that are constructed as porous stone surfaces of the loading door.
The movement of the loading door from the closed position into the opened position follows a simple configuration so that the loading door can be moved vertically upward for opening the loading opening, wherein the channel covering covers the nozzles directed into the loading channel, and the suction device arranged in the lower region of the loading door is moved from the closed position against the lower channel wall and into the upper region of the loading channel.
The channel covering and the lower channel wall are made of fireproof material, like the loading door or flap. The loading device for the batch can be constructed as a loading trowel in one embodiment.
This invention can also be used in equally advantageous ways with other configurations of the loading opening and the loading systems.